Diffusion Short Title : Introduction to Interfaces and Diffusion

This chapter covers selected fundamental topics in Materials Science, with the purpose of introducing certain concepts that will serve as a foundation for other chapters in this volume. The topics addressed include: interfacial Gibbsian thermodynamics, with special emphasis on adsorption (or interfacial segregation) phenomena; statistical thermodynamic treatments of interfacial segregation, with examples of the relationship between interfacial composition and thermodynamic properties of two-component materials, as well as the consequences of variations in interfacial composition on interfacial energy; anisotropy of interfacial energy and the effects of composition thereon; grain boundary structure and energetics; interfacial equilibrium in solid-vapor, solid-liquid and solid-solid systems; and finally a brief overview of diffusion in solid metals which introduces both the mathematical framework as well as atomistic aspects of diffusion mechanisms.